There is absolutely no way to do this. Even if you find files that used to belong to a now delete user, you'll only get their former numeric user ID; you cannot rely on verbose log files containing user names, etc.
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Daniel Beck♦Jul 23 '11 at 18:13

Gives one account name for every user removed from the system, in this format. It doesn't matter how long ago it was removed as long as the com.apple.preferences.accounts.plist file itself is not tampered with: